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  <div class="section" id="old-buffer-protocol">
<span id="abstract-buffer"></span><h1>Old Buffer Protocol<a class="headerlink" href="#old-buffer-protocol" title="Permalink to this headline">¶</a></h1>
<p>This section describes the legacy buffer protocol, which has been introduced
in Python 1.6. It is still supported but deprecated in the Python 2.x series.
Python 3 introduces a new buffer protocol which fixes weaknesses and
shortcomings of the protocol, and has been backported to Python 2.6.  See
<a class="reference internal" href="buffer.html#bufferobjects"><em>Buffers and Memoryview Objects</em></a> for more information.</p>
<dl class="function">
<dt id="PyObject_AsCharBuffer">
int <tt class="descname">PyObject_AsCharBuffer</tt><big>(</big><a class="reference internal" href="structures.html#PyObject" title="PyObject">PyObject</a><em>&nbsp;*obj</em>, const char<em>&nbsp;**buffer</em>, Py_ssize_t<em>&nbsp;*buffer_len</em><big>)</big><a class="headerlink" href="#PyObject_AsCharBuffer" title="Permalink to this definition">¶</a></dt>
<dd><p>Returns a pointer to a read-only memory location usable as character-based
input.  The <em>obj</em> argument must support the single-segment character buffer
interface.  On success, returns <tt class="docutils literal"><span class="pre">0</span></tt>, sets <em>buffer</em> to the memory location
and <em>buffer_len</em> to the buffer length.  Returns <tt class="docutils literal"><span class="pre">-1</span></tt> and sets a
<a class="reference internal" href="../library/exceptions.html#exceptions.TypeError" title="exceptions.TypeError"><tt class="xref py py-exc docutils literal"><span class="pre">TypeError</span></tt></a> on error.</p>
<p class="versionadded">
<span class="versionmodified">New in version 1.6.</span></p>
<p class="versionchanged">
<span class="versionmodified">Changed in version 2.5: </span>This function used an <tt class="xref c c-type docutils literal"><span class="pre">int</span> <span class="pre">*</span></tt> type for <em>buffer_len</em>. This might
require changes in your code for properly supporting 64-bit systems.</p>
</dd></dl>

<dl class="function">
<dt id="PyObject_AsReadBuffer">
int <tt class="descname">PyObject_AsReadBuffer</tt><big>(</big><a class="reference internal" href="structures.html#PyObject" title="PyObject">PyObject</a><em>&nbsp;*obj</em>, const void<em>&nbsp;**buffer</em>, Py_ssize_t<em>&nbsp;*buffer_len</em><big>)</big><a class="headerlink" href="#PyObject_AsReadBuffer" title="Permalink to this definition">¶</a></dt>
<dd><p>Returns a pointer to a read-only memory location containing arbitrary data.
The <em>obj</em> argument must support the single-segment readable buffer
interface.  On success, returns <tt class="docutils literal"><span class="pre">0</span></tt>, sets <em>buffer</em> to the memory location
and <em>buffer_len</em> to the buffer length.  Returns <tt class="docutils literal"><span class="pre">-1</span></tt> and sets a
<a class="reference internal" href="../library/exceptions.html#exceptions.TypeError" title="exceptions.TypeError"><tt class="xref py py-exc docutils literal"><span class="pre">TypeError</span></tt></a> on error.</p>
<p class="versionadded">
<span class="versionmodified">New in version 1.6.</span></p>
<p class="versionchanged">
<span class="versionmodified">Changed in version 2.5: </span>This function used an <tt class="xref c c-type docutils literal"><span class="pre">int</span> <span class="pre">*</span></tt> type for <em>buffer_len</em>. This might
require changes in your code for properly supporting 64-bit systems.</p>
</dd></dl>

<dl class="function">
<dt id="PyObject_CheckReadBuffer">
int <tt class="descname">PyObject_CheckReadBuffer</tt><big>(</big><a class="reference internal" href="structures.html#PyObject" title="PyObject">PyObject</a><em>&nbsp;*o</em><big>)</big><a class="headerlink" href="#PyObject_CheckReadBuffer" title="Permalink to this definition">¶</a></dt>
<dd><p>Returns <tt class="docutils literal"><span class="pre">1</span></tt> if <em>o</em> supports the single-segment readable buffer interface.
Otherwise returns <tt class="docutils literal"><span class="pre">0</span></tt>.</p>
<p class="versionadded">
<span class="versionmodified">New in version 2.2.</span></p>
</dd></dl>

<dl class="function">
<dt id="PyObject_AsWriteBuffer">
int <tt class="descname">PyObject_AsWriteBuffer</tt><big>(</big><a class="reference internal" href="structures.html#PyObject" title="PyObject">PyObject</a><em>&nbsp;*obj</em>, void<em>&nbsp;**buffer</em>, Py_ssize_t<em>&nbsp;*buffer_len</em><big>)</big><a class="headerlink" href="#PyObject_AsWriteBuffer" title="Permalink to this definition">¶</a></dt>
<dd><p>Returns a pointer to a writeable memory location.  The <em>obj</em> argument must
support the single-segment, character buffer interface.  On success,
returns <tt class="docutils literal"><span class="pre">0</span></tt>, sets <em>buffer</em> to the memory location and <em>buffer_len</em> to the
buffer length.  Returns <tt class="docutils literal"><span class="pre">-1</span></tt> and sets a <a class="reference internal" href="../library/exceptions.html#exceptions.TypeError" title="exceptions.TypeError"><tt class="xref py py-exc docutils literal"><span class="pre">TypeError</span></tt></a> on error.</p>
<p class="versionadded">
<span class="versionmodified">New in version 1.6.</span></p>
<p class="versionchanged">
<span class="versionmodified">Changed in version 2.5: </span>This function used an <tt class="xref c c-type docutils literal"><span class="pre">int</span> <span class="pre">*</span></tt> type for <em>buffer_len</em>. This might
require changes in your code for properly supporting 64-bit systems.</p>
</dd></dl>

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